Delete all topic subscription SNS

The behavior you are experiencing is expected since subscriptions are orphaned when a topic is deleted without the subscriptions being deleted first. In such case, the subscriptions linger in the system until an internal tool cleans them up.

Every topic is unique in the system, even if they share names. That being said, if the deleted topic is recreated with the same name, the orphan subscriptions can temporarily receive the new topic's traffic due to eventual consistency. After 15 minutes however, the system will be consistent and any orphan subscriptions leftover from the old topic will no longer get messages published to the new topic.

Our service team has indicated to me that they are currently working on improving the clean-up process of orphan subscriptions. More specifically, they'll be making their deletion substantially faster with the goal of making customer accounts cleaner and not littered with leftover resources. Please note that unfortunately, we wont be able to provide any ETA for internal updates.

Was this a previously used topic? Topics that are recreated might sometimes run into some errors.

If that isn't the case then try some of the troubleshoot documentation and see if your issue falls under this, failing that you should contact AWS Support to remove the subscriptions for you.